1. Field
The invention relates to relay devices that have a plurality of input/output modules each including input/output ports and that relay communication packets by transferring the communication packets between the input/output modules, and to band controlling methods for controlling the relay devices. More particularly, the invention relates to a relay device capable of realizing band control without complication of a configuration and to a band controlling method.
2. Description of the Related Art
Recently, to realize provision of stable network services, relay devices, such as routers and network switches, include a band controlling function for controlling a band for each network service or each user. For example, Japanese Unexamined Patent Application Publication No. 2005-260430 discloses a technique for temporarily storing communication packets in an output queue provided for each output (transmission) port to perform band control based on an amount of the accumulated communication packets.
Meanwhile, some relay devices have a configuration that allows the number of input/output modules having a plurality of ports to be freely increased or decreased so that the configuration of the device can be flexibly changed according to the increase or decrease in the necessary number of ports. When the technique disclosed in Japanese Unexamined Patent Application Publication No. 2005-260430 is applied to such relay devices, a path for informing another input/output module of an amount of communication packets accumulated in each output queue is needed, which undesirably complicates the configuration.